but for "invention relates to wooden kayaks made of wooden panels that are stitched together and glued at the joints, after which the entire kayak is covered inside and out in fiberglass" so it might not be a concern for many.

However, Note Part 10 of Patent 67747:

10. A method of forming a cockpit for a kayak having a deck defining a cockpit opening, the method comprising the steps of:

This means the patent is also for a method of making this kind of cockpit. I.e. if you use panels of material to make a plug, then the fiberglass kayak made from that plug also infringes. So, this pertains to all composite kayaks, because, this is pretty much how one makes a plug. In the US, even non-commercial use can be an infringement.

Anyway I'm pretty sure I've seen a recessed cockpit with plywood boats before 2002 year but obviously no one patented this before.

More specifically, in the application for this patent no prior art showing recessed cockpits were provided to the patent examiner, so based on on what the examiner was aware of, this recess was a new innovation and thus patentable. Patent examiners don't need to be experts in things like kayaks so it is possible to get patents on ideas that are old, or invented by someone else.

This patent never should have been approved, but it was, so it can be used to attempt to scare people away from incorporating a common feature in their designs.

A Blazing Aspen "Murrellet" kayak from Sea Kayaker Magazine in April 2000